I would personally invest in a good HRM over the Fitbit. I looked into both the Bodybugg and Fitbit about a year and a half ago. While some of the features are interesting, when it comes down to it, the best measure from a fitness standpoint - which is what I really wanted it for - will come from a quality HRM.

I have a bodymedia. I've had it 4ish years now. While I pay a fee for it, I like the stats, and I feel it's been worth itself. I know a bunch of ladies on a different group with fitbits and a few others, and it seems their fitbits seem inaccurate, on numbers at times.